Core A (Clinical Core) has three goals: 1. to enroll and characterize all patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS); 2. to provide access to patients and clinical samples from selected patients with ALI/ARDS or from those at risk for ALI/ARDS for the SCOR research projects; and 3. to facilitate coordination within this SCOR and among ALI SCOR. This Core has the following four specific aims: 1. Registry of Patients with Major Trauma At Risk for ALI/ARDS (Trauma Cohort): To develop a prospective registry of patients with major trauma admitted to Surgical Intensive Care Unit (ICU) at the Hospital of the University of Pennsylvania (HUP) and the Medical-Surgical ICU Brandywine Hospital (BWH) who are at risk for developing ALI/ARDS in the first 5 days after trauma. This registry will form the basis of the prospective cohort and nested case-control studies of patients with major trauma in Projects 1 and 3. 2. Registry of Patients with Sepsis At Risk for ALI/ARDS (Sepsis Cohort): To develop a prospective registry of patients with sepsis admitted to the ICUs who are at risk for developing ALI/ARDS in the first 5 days after onset of sepsis. This registry will form the basis of the prospective cohort and nested case-control studies of patients with sepsis in Projects 1 and 3. 3. Registry of All Patients with ALI and ARDS: To develop and maintain a prospective ALI/ARDS Registry by identifying intensive care unit (ICU) patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Subsets of this registry, i.e., patients with ARDS associated with major trauma or sepsis, will be used for the prospective cohort studies of ARDS in Projects 1 and 3 and will be enrolled as subjects in the randomized clinical trial of dl-alpha tocopherol as an anti-oxidant in Project 3. 4. Organized Clinical Data and Sample Collection System for Patient Populations under Study: To provide an organized system to collect and enter clinical data into the SCOR Central Data Base and to collect and distribute samples of blood and urine for the prospective cohort and nestled case-control studies involving patients who are at risk for ALI/ARDS (Specific Aims 2 and 3, above) in Projects 1 and 3 as well as the studies of patients with ARDS (Specific Aim 3, above).